1. Field of the Invention
The present invention relates to a stroboscopic control method used in an electronic still camera, especially, at a frame-recording time at which a frame is recorded in a state in which there is a difference in time between first and second fields.
2. Description of the Related Art
In general, there are the following two exposure control methods using a stroboscope in a general photographing operation.
(1) In a first method, a full constant quantity of light is emitted from the stroboscope without controlling the light quantity, and an exposure amount is controlled by the operating of a diaphragm.
(2) In a second method, an operation of the stroboscope is controlled such that the diaphragm is constant and light reflected from a photographed object is measured to make a quantity of the reflected light constant. This second method is called a so-called automatic stroboscopic system.
Recently, the record of a frame picture image having an excellent quality has been required. In the case of this frame picture image, first and second fields are set to one frame. As a method for inputting this frame, there is a method for inputting and recording the frame picture image constructed by a total of the first and second fields having a time difference of 1/60 second. This method is called a movie frame recording method in the following description. However, a time for inputting the frame picture image is long in this movie frame recording method. Accordingly, there is no field recording method for performing a stroboscopic synchronous operation with respect to the first and second fields. There is a field recording method for performing the stroboscopic synchronous operation with respect to the first or second field. However, this field recording method has a problem that resolution is reduced in the field record.
There is a known movie frame recording method for performing the stroboscopic synchronous operation by using a mechanical shutter. However, in this movie frame recording method, since the mechanical shutter is used, structure and control of the mechanical shutter are complicated. For example, it is necessary to dispose a shutter driver in addition to the mechanical shutter.
As a movie frame recording method without using the mechanical shutter, there is a known method for inputting and recording a movie frame. This method is similar to a method for taking a moving picture in a movie (or a cam coder). However, there is no such method for performing a stroboscopic synchronous operation.
As mentioned above, in the movie frame recording method using a mechanical shutter, it is possible to perform the stroboscopic synchronous operation when a movie frame is recorded, but the structure and control of the mechanical shutter are complicated. In contrast to this, resolution is reduced in the field recording method for performing the stroboscopic synchronous operation with respect to one of the first and second fields. Further, no movie frame recording method without using the mechanical shutter is disclosed.